


The sins of Hogwarts

by CrystxlChxrry



Category: Harry Potter - J. K. Rowling, 七つの大罪 - 鈴木央 | Nanatsu no Taizai | The Seven Deadly Sins - Suzuki Nakaba (Anime & Manga)
Genre: Alternate Universe - Harry Potter Setting, Crossover, How Do I Tag, Nanatsu no Taizai | The Seven Deadly Sins Manga Spoilers, Other Additional Tags to Be Added, Seven Deadly Sins, Tags Are Hard
Language: English
Status: In-Progress
Published: 2019-12-21
Updated: 2020-05-13
Packaged: 2021-02-26 03:27:25
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 7
Words: 7,880
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21886654
Author URL: https://archiveofourown.org/users/CrystxlChxrry/pseuds/CrystxlChxrry
Summary: After another defeat of Voldemort, professor Albus Dumbledore decides that it is necessary to get extra protection for his school- and, more specifically, one boy in particular. After hearing about a group of seven sinners, he wonders if it is worth taking this chance.Meanwhile, the seven deadly sins are free from adventure for a while, although naturally, it does not last. The two worlds collide, and will this force of Knights really be enough to defend the students?(HIATUS I'M SORRY)
Relationships: Diane/Fairy King Harlequin, Elizabeth Liones/Meliodas
Comments: 52
Kudos: 115





	1. Chapter 1

In Hogwarts, professor Albus Dumledore was pacing around his office. It was the summer holidays, so Harry was safely at home with his aunt and uncle, but only last year, his first year at Hogwarts, he had defeated the dark Wizard Voldemort. Not completely defeated, only stopped his plans. For now. Dumledore would personally be happy if Harry never had to get in a situation like that again, but he was courageous, and wanting to get revenge for his parent's deaths. It was only one week until Harry came back to Hogwarts, and Albus was sure that Voldemort was going to try something again. He adjusted his half-moon glasses, and suddenly saw something on his desk. A pile of paper that he was quite sure that he had never seen before. He slowly walked over, frowning, and picked up the sheets. The seven deadly sins, a group of powerful traitors who have incredible powers. The seven deadly sins? Dumledore had never heard of them before. The dragon's sin of wrath, Meliodas... The serpent's sin of envy, Diane... The foxes sin of greed, Ban... The grizzly sin of sloth, king... The goat's sin of lust, Gowther... The boar's sin of gluttony, Merlin... And the lion's sin of pride, Escanor... So they had all committed sins. Wrath, envy, greed, lust, gluttony and pride... Was it safe to let people bearing such titles into his school? It hadn't said what sin any of them had committed, so he had no idea if they were criminals, or if they had been cleared. Or even if they were still alive. He carried on pacing the office. Perhaps he could talk to them, if he could find a way to contact them. He went back to reading the papers. Also owners of 'the boar hat', a traveling tavern.  
Albus Dumledore smiled as his phoenix, Fawkes, landed on his arm.

Merlin teleported outside the boar hat, and heard the usual pandemonium. When she opened the door, she saw tables upturned, smashed bottles of ale laying on the floor, and in the middle were Ban, king, human-sized Diane, and Meliodas. She sighed.  
"Captain. We have an urgent message from the king." As expected, he was fast asleep. Sighing again, the Mage walked over to him, and shouted, "CAPTAIN!"  
He opened his eyes, blinking. "Oh hey Merlin, I didn't know you could be so loud." Suddenly, Elizabeth, hearing Merlin's shout, ran downstairs.  
"Lady Merlin! You startled me!"  
The others were also starting to wake. "Oh, Merlin?" Said Diane sleepily.  
The boar's sin sighed, again. "Now you're awake, captain, the king has called us all for an urgent meeting." The goat's sin of lust, Gowther, also walked downstairs.  
"A meeting? What about?" Meliodas said, sitting up and rubbing his eyes.  
"He hasn't told me." She looked at her comerades, and grinned. "You all seem awake enough." She teleported all of the sins to Liones castle.

King Bartra was sat in his throne, as usual. "Ah, you have arrived." The sins stood in front of him, Ban still half-asleep. "I have called you together because of something that arrived, addressed to the seven deadly sins. It was a burning, red feather, with this note attached to it." He passed the note to Meliodas.  
"To the Seven Deadly Sins," he read out. "I have sent you this letter from a different world, it seems, with a request that you talk to me. Right now on Hogwarts, which is my school, a dark Wizard named Voldemort is attempting to revive himself, and trying to kill one of our students. If you would be so kind as to meet up, I will explain the details. If you decide to come, just all of you hold this letter two hours after receiving it. It is a portkey, and will take you all instantly to me. Yours sincerely, Albus Dumledore." After reading, he looked up to see what his comerades' reactions were. Merlin picked up the letter to examine, while Ban thought about it.  
"There is defiantly magic in this paper," Merlin informed them.  
Ban said, "If some 'dark Wizard' geezer is trying to murder some kids, it might be worth stopping him."  
"You're right, Ban," Meliodas said. Diane and king nodded in agreement, while Merlin continued to examine the paper. Gowther simply watched.  
"How intriguing," Merlin murmured. "I've never sensed this type of magic in my life before. I would be most interested to see where it comes from." She smiled slyly at her friends.  
"I say we see what this is all about," said Meliodas decisively. The others nodded in agreement. "So we hold this in... It's been here for about an hour, right?" When Bartra nodded, he said, "ok, Merlin, can you take us back to the boar hat then?" The Mage teleported the sins back to the tavern, where they were greeted by Elizabeth and Hawk.  
"Oh, Sir Meliodas! You're alright!" Elizabeth said with delight. He responded by groping her, until Hawk kicked him out of the way.  
"Elizabeth, take this chance to run!" She laughed slightly, blushing.  
"So, the Princess and sir hawk will be coming with us, I assume?" Merlin stated.  
Meliodas told Elizabeth what was happening, and she instantly decided to come. Meliodas grinned at her confidence.  
"So we just wait an hour?" Hawk questioned. The sins nodded.

An hour later, the sins, along with Elizabeth and Hawk, were holding the small piece of paper. "What will it do?" King asked with curiousity.  
Merlin responded with, "just wait, I suppose."  
Suddenly, the paper began to glow, and the group felt at if they had been hooked behind their navels, and were instantly blown off their feet, into the unknown.

All eight of them landed on the floor in a circular office, knocking over a small table with an amount of silver trinkets that were emitting smoke. Merlin instantly stood up, examining them with interest.  
"I see that you like my trinkets," said an old voice, with a slight laugh. The sins all turned around to see an ancient man with a long, silver beard, and half-moon glasses watching them. "So you must be the seven deadly sins."  
Meliodas smiled. "I'm assuming you are Albus Dumledore. Nice to meet you." They shook hands. "Let me introduce my team. I'm Meliodas, the dragon's sin of wrath, this is Ban, the foxes sin of greed, this is Merlin, the boar's sin of gluttony, this is Gowther, the goat's sin of lust, this is Diane, the serpent's sin of envy, this is king, the grizzly sin of sloth, and this is Elizabeth." They all - with the exception of Gowther - smiled at the old Wizard.  
"Don't forget me, the mighty sir Hawk!" Said the pig. Nobody took any notice of him, to his annoyance.  
"Oh? So miss Elizabeth is not one of the sins?" Asked Dumledore.  
"Nope, she's the Princess of Liones. The sin of pride Escanor was busy somewhere."  
Dumledore said, "So, if I may ask, what are all your sins?"  
Meliodas blinked. "As an order of Knights, we have put the past behind us. But each of us have committed a sin. It's up to them if they tell you what." All of the sins shook their heads, saying that they didn't want to.  
"So," said Meliodas, walking up to him. "What was it that you were wanting to speak to us about?"  
"Ah. So, let me fill you in. A decade ago, a Wizard named Voldemort murdered two people - Lily and James Potter. He had the intent of killing their child, Harry potter, but for unknown reasons, his curse failed, and Harry rebounded it back at him. Some believed he died, but only a few months ago, Voldemort was here in my school, taking possession of somebody named professor Quirrel. Harry managed to fight him, and beat him, but I'm worried that he will be back, and try to kill him again. What I would like is for you all to protect Harry." Silence met this.  
"We would like to talk about this, if you wouldn't mind," said Merlin. The group walked over to the corner.  
"What do you all think about this?" Meliodas asked. "Gowther, is he being truthful?"  
The goat's sin nodded. "I don't believe he would ever lie after what happened in his past."  
King spoke up. "I think we should protect this boy." Diane nodded in agreement.  
Merlin smirked. "And I'm most interested in this school. I would like to stay and observe it for a while."  
"So, we're staying?" They all nodded, including Elizabeth. They walked back over to Dumledore.  
"We say yes."  
Dumledore smiled in appreciation. "Thank you."

**Notes for the Chapter:**

> Hello! I want to thank you for reading this fanfiction  
> I started writing the first few chapters in February 2019, and have recently come across them again. So if the first four chapters are not well written then I can assure you that after that they will improve in quality. I will update as soon as I can :)


	2. Chapter 2

**Notes for the Chapter:**

> I know I'm not supposed to post too much in one day so I'll probably just do these two chapters but I know I'll forget tomorrow I hope nobody minds-

"So, here is my plan. Each of you will pretend to be students from a different school, which was destroyed in a recent war, so you moved here. However, Miss Merlin and Mr Ban would not be able to pass off as students as easily as the rest of you..." Dumbledore told them.  
Merlin smiled slyly. "No need to worry about that, I can disguise the two of us."  
Dumbledore nodded. "So, if you would like, you can remain here for the last week until the students arrive." They all nodded. "Two more things - you will have to act like students, so that means attending lessons, wearing uniforms, even getting sorted into a house. Are you all ok with that?" They nodded again.  
"You said there were two things," Meliodas reminded him.  
"The second thing is that you will not be able to carry your weapons around with you,'' he said, indicating Lostvayne and Chastiefol.  
"I'm sure I'll find a way to deal with that, too," Merlin told him.  
"Ok, so you can remain here for a week now," Dumbledore told them with a smile. "Would you like anything to eat?"

He lead them down into the castle, and into the great hall. Ban looked excited as he walked into the large hall, with floating candles and the enchanted ceiling. It wasn't just him who was excited. Merlin looked incredibly pleased with the enchanted ceiling, and was most likely going to study it later. Gowther looked as emotionless as always, and king floated on Chastiefol, looking around the large space and four tables. Diane seemed to enjoy the large space, and Hawk ran up through the hall. Elizabeth and Meliodas walked side by side, looking in curiosity at their surroundings.  
"Please, sit wherever you would like," said Dumbledore with a warm smile. They all sat down at the Gryffindor table, and plates of food instantly appeared before them. All of them - with the exception of Gowther - instantly grabbed a plate, and started eating. Ban passed food down to Hawk, who ate with pleasure.  
"Woah, who made this?! It's almost as good as Ban's cooking!" He carried on eating.  
Dumbledore saw that Gowther was not eating. "Do you not want food?" He asked the pink-haired goat's sin, who shook his head.  
"I have no need to eat," he replied in his usual monotone.  
After eating, Albus lead them to the Hufflepuff common room to sleep, as it was nearest.

Over the week, Merlin was busy. First of all, she managed to create a spell for all of their sacred treasures to be summoned at will. She then called Diane, and made her a necklace so that she could stay small until she took it off. Today, she had told Ban to come, and had not yet emerged.  
"Oh yeah, Dumbledore, it seems fine to tell you what race we all are," Meliodas said. "Just so you don't get nervous, the races from our world are very different from yours. Let's see... Ban is an immortal." These words caused Albus' eyes to widen. "Merlin... I don't even know, King is a fairy," again, Dumbledore looked surprised. "Diane is a giant.'' The Wizard looked like he was going to interrupt, but he didn't. "Gowther... A doll." This time he did interrupt.  
"A- a doll? How can a doll..?"  
"He was created by a Wizard 3000 years ago. And he's still our valued comerade. Oh, and I'm a demon."  
Dumbledore still looked surprised from this information. Suddenly, Merlin and Ban walked out. Except that they looked like teenagers. Meliodas gave a tiny snigger to see Ban as a teenager.  
Merlin had done a good job. It would have been impossible to tell that they both normally had the appearance of adults, if they hadn't all already known them.  
"Excellent! Now all we need is to give you all wands and a uniform!" Said Dumbledore with delight.  
Merlin looked up instantly, her teenage face alight with interest. "Wands? Will we be able to use them with our powers? I need to research this."  
Smiling at her curiosity, Dumbledore led them over to a cabinet with a selection of wands in. "I thought you could all give them a try, and see if any of them work for you."  
Of course, Merlin was the first up, trying each wand. She was closely followed by the others, who each tried one. There was a burst of light, and king looked at the wand he held in surprise. It felt warm and almost familiar in his hands.  
"It looks like you have found your wand," said a still smiling Dumbledore. It was a narrow strip of wood, made from an olive tree, containing a unicorn hair.  
The next person to find their wand was the goat's sin Gowther. He had picked up the wand, and felt the same feeling that king had. He tilted his head slightly. It was made from pine wood, and was quite thin with a pheonix feather in.  
To her delight, Merlin got her wand next. It had a stick of weeping willow, and contained a unicorn hair. She wanted to instantly examine it, but waited for the others.  
Next was Diane. Hers was a stick from a northern red oak, and contained a dragon heartstring. She was very pleased with it.  
Then Meliodas got a thick strip of maple wood, with a dragon heartstring in. Ban got horse chestnut wood, with a pheonix feather, and finally, Elizabeth got a unicorn hair core, and silver beech wood.  
"So, everyone has a wand now! I wasn't sure if it would work for you, but it looks like it did. So, tomorrow everyone will be arriving. Please do whatever you want until then." He smiled at them.  
They all walked off to do their own thing - Meliodas and Elizabeth to explore some more, Diane to look around outside, King to most likely follow her, Gowther to the library, Ban explore with Hawk, and Merlin to examine her new wand.


	3. Chapter 3

Dumbledore called all of the sins, to tell them that the Hogwarts express was nearly arriving. He told them to wait in a chamber by the great hall, until the students arrived. Ban and Merlin had bracelets to keep them looking like teenagers, and Diane had hers for keeping her small - Gowther also had one for keeping his powers under control, like always. Dumbledore told them that they would be sorted into houses with the first years but have the second years timetable, so they could keep an eye on Harry.  
Each of them had their wands, and were dressed in the black school uniform.  
Ban frowned. "Why do we have to wear these things?" He complained.  
Meliodas replied with, "Well, we're pretending to be students. I know it's rubbish, but we'll have to wear it for now."  
While they were waiting for the students to arrive, Meliodas was talking to Elizabeth.  
"So, what do you think of Hogwarts so far, Elizabeth?" He said with a grin.  
"It's so big! And there's so much here! I haven't even explored a quarter of it! What about you, sir Meliodas?" She replied with shining eyes.  
Meliodas, however, frowned. "Y'know, you can't call us sir or lady while we're here."  
She looked confused. "Why not?"  
He gave a small smile. "Don't you think the kids will realise that something is up if you talk to us in a posh way like that?"  
She blushed for not realising, and sighed with a smile. "I'll try." She then turned to him with anxiety. "But what if we are sorted into different houses?"  
Meliodas grinned. "Who says people from other houses can't meet up? Anyway, I'm sure you'd be with a sin to protect you."  
Suddenly, they heard the sound of a train outside, and Dumbledore strode over to them.  
"That's the Hogwarts express arriving. If you will, please all wait in here." He showed them to the room where first years waited before being sorted, where they all waited for a few minutes. They heard the doors open, and the entrance hall was suddenly full of students, all wearing the Hogwarts robes, and all chatting and grinning. After the tidal wave of children, some more followed but all in smaller groups. When they had all got into the great hall, the doors opened again, and a giant of a man strode in, along with a lot of smaller students. They all looked nervous and scared. The giant man herded them over to a strict-looking woman, who's hair was in a tight bun. She looked like she sort of person not to get on the wrong side of. They exchanged a brief word, and she then led the children over to the room where the sins were waiting. The doors burst open, and Dumbledore walked over to the woman, and told her quietly about the sins, but told her that they were from a destroyed school, and had joined Hogwarts. She nodded, and then the man walked past her into the great hall. She turned to face them all.  
"So, welcome to Hogwarts," she began. She had a strict voice too. "First years, you are going to get sorted into your houses first. For anyone who doesn't know, they are Gryffindor, Slytherin, Ravenclaw, and Hufflepuff. We will have the feast, and you will then listen to your house prefects, and they will show you to the common rooms. Any questions?" When there were no responses, she said, "Follow me, then," and led the group into the great hall.  
It looked amazing. The floating candles lit up the room like tiny stars floating around, and the enchanted ceiling twinkled in a welcoming way. The first years stood in a line in the middle of the great hall, some looking around the hall for relatives, some nervous, some confident. A red-haired girl was being watched from the Griffindor table by three who must have been her brothers, as they all had the exact same red hair. Dumbledore stood at the front of them, with a stool in front of him. The teacher who had showed them into the hall carried a ragged, ancient Wizard's hat up to the stool, and placed it on it. It seemed like the whole school was watching it. Suddenly, it burst into song.  
It sung about Hogwarts, about the four houses and their qualities. It also spoke of four people - Godric Griffindor, Salazar Slytherin, Rowena Ravenclaw, and Helga Hufflepuff. Merlin was watching the hat with intense curiosity, as if it were costing all of her self control not to run over and examine it. The rest of the sins were watching the hat along with the first years, but suddenly they heard something outside that the students hadn't, and all turned their heads. What seemed to be a small car was flying through the sky, and plummeting to the ground. They thought it would hit the ground, but instead it fell into a tree. However, they sensed a magical power coming from the tree, and it started moving by itself, and hitting the car repeatedly. It looked like the people in the car were going to be murdered, but unseen to all but Meliodas, Merlin had used a little magic to allow the car to fall from the tree. It carried on trying to attack the car, which had quickly moved away. It's drivers jumped out, along with an owl, and the car sped off into a forest. The people who were in it stood up, and looked at the great hall. The sins looked away, because the sorting hat had finished it's song, and it was sorting time.  
Before the professor could start calling names from the list, Dumbledore stood up.  
"Before we start this year's sorting, I would like to put it to all your attentions that 7 students will be joining us here who are from another school, but their school got destroyed in a recent war. They have chosen to join our school." He sat back down, indicating for the woman to start calling names from the list.  
"Ban." She called first. He strode up, slouching as usual, and shorter than normal, thanks to Merlin's spell, and it was his blue hair that attracted attention. He walked up to the stool, and put the hat on his head. It considered him for a moment, and then shouted, "Slytherin!" There was clapping from the green and silver table, and when Ban sat down there, and white-haired second year shook his hand.  
"Hi, my name's Mayfoy, Draco Mayfoy," he told Ban, a sneer on his face and arrogance in his eyes. The fox sin instantly didn't like him.  
Another name was called. "Merlin." Her name alone attracted a vast amount of attention. Everyone looked at her, curiosity in their eyes. "Merlin?" Mayfoy hissed. "Like the great Wizard?" Ban shrugged. Many of the students' eyes widened when she had heard the name.  
Merlin walked up to the stool with dignity, and put the ragged hat on. Almost instantly it yelled, "Ravenclaw!" There was clapping from the blue and bronze table, where the Mage walked to, and sat down by herself.  
"Harlequin." Was said next. The fairy walked up nervously. As he was not supposed to fly, he had been told to walk, and was slightly uncomfortable with it. When he put the hat on his head, it took a moment before shouting, "Hufflepuff!" The grizzly sin looked quite pleased as the walked over to the yellow and black table.  
"Gowther." The sin of lust walked to next, his face emotionless like always. "Ravenclaw!" Was shouted almost as quickly as it had been for Merlin. He walked over and sat next to the boar's sin, who gave him a smirk. Their fellow Ravenclaws looked at him, slightly nervous because of his emotionless expression.  
Next up was Elizabeth. She walked up with anxiety clear in her face, and some of the boys were watching her and grinning. Meliodas glared at them all. The hat decided for a minute, although it felt like an hour, and then shouted, "Hufflepuff!" She looked pleased, and ran over to the table of friendly students.  
"Diane." She was instantly sorted into Gryffindor. She looked at king apologetically, and ran over the table of clapping students. Meliodas joined her straight after. Elizabeth looked at him sadly, but was sitting next to king, who was friendly with her.  
Next the students were sorted. A girl called Ginny Weasley joined Diane and Meliodas, and another called Luna sat next to Merlin at the Ravenclaw table. She was wearing what seemed to become radish earrings, but the Mage sensed a slight magical power coming from them. She made up her mind to ask her about them later.  
Suddenly, the great hall doors burst open, and a black-haired professor strode in commandingly. He wore an angry expression on his face, and spoke to Dumbledore and the woman.  
Dumbledore stood up. "To the new students - welcome. To the older students - welcome back. It seems that some of you still need reminding that going on the dark forest is completely forbidden," his twinkling eyes focused on the red haired Gryffindor twins, who grinned in return. "There is much to say, but first you all need to eat." He waved his wand, and suddenly every table was full of food. The students laughed with pleasure, and most of them didn't even notice the three professors leaving the great hall.  
At the Gryffindor table, a bushy-haired girl was at opposite Meliodas and Diane.  
"Hi, my name's Hermine Granger," she said with a friendly smile. They both smiled in return.  
"Hi, I'm Meliodas and this is Diane. Can you tell us about the professors?" Said Meliodas with a grin. She nodded.  
"I assume you know professor Dumbledore? Well the ones who left when him - the woman was professor McGonagall and the black-haired man was professor Snape. McGonagall is the head of our house, Gryffindor, and Snape is the head of Slytherin. The other professors," she pointed at a tiny man sat at the staff table, "he's professor Flitwick, head of Ravenclaw. Also, the girl from your school called Merlin - is she related to the great Wizard Merlin?" Hermione asked with interest.  
Diane replied briskly with, "Nope, that's just her name."  
The bushy-haired Gryffindor looked slightly disappointed, but she pointed at a woman who had slightly patchy robes and messy hair. "That's professor Sprout, she's the head of Hufflepuff." She began helping herself to food. "So, were there other students from your school or just all of you?"  
Meliodas quickly thought, and then said, "We were the ones who survived." Hermione shivered sightly.  
"What was it like at your school?" She asked.  
Diane decided to reply. "We each had as different type of magic that we learnt, and we also did physical strength. Instead of just wands, we each had a weapon, for example, I had a battle hammer, and Meliodas had a sword." Hermione looked incredibly interested now.  
"You did magic with weapons?" She said in wonder. However, before she replied, the doors opened again, and professors Dumbledore and Snape entered. They were followed a few minutes later my McGonagall. They ate the rest of the feast without interruption. When they had eaten as much as possible, Dumbledore stood up, and smiled at his students.

**Notes for the Chapter:**

> LMAO WHEN I WAS DRAFTING THIS I WROTE PERFECTS INSTEAD OF PREFECTS and I don't think you understand how many times I misspelled Gryffindor


	4. Chapter 4

**Notes for the Chapter:**

> I wrote this chapter on my phone so the capitalisation is dumb I'm sorry-

A small pink face looked up from under the table.  
"Hey Meliodas, I'm bored," said Hawk. Hermione looked at him with wide, curious eyes, but didn't speak, as Dumbledore was about to start.  
Meliodas whispered, "go sit with Ban then." Hawk glared at him and ran over to the Slytherin table.  
Dumbledore smiled at his students. "Welcome! Welcome to Hogwarts! Now, for our first years, the dark forest is completing forbidden, and hopefully a few of our older students will have remembered that, too," said Dumbledore, his eyes twinkling. Meliodas noticed two red-haired twins grinning at this. He wondered if the sins would have to abide by the rules. Dumbledore carried on talking.  
"And the quidditch trials will be held whenever the team captain wants to. First years are not allowed their own broomstick. Also, nobody below third year can go to Hogsmeade, and third years and above need a permission slip up go." Meliodas lost interest and instead looked around the great hall for a few minutes.  
"... And after that feast, I know you're all tired and have not listened to anything that I just said. Time to go to bed! Goodnight!"  
There was a scraping noise as everyone stood up at once, and rushed to get to their common rooms. Hermione was still stood next to Meliodas and Diane.  
"Do you want me to show you where the common room is?" She asked them. Meliodas decided not to tell her that they had already toured the castle.  
"Sure," he smiled. They both followed the Gryffindor to their common room. However, when they reached the Fat Lady portrait, another red-haired boy, who was probably related to the twins Meliodas had seen, and a boy with black, messy hair, were standing outside the common room entrance, with looks of dismay on their faces.  
"Harry! Ron!" Hermione ran forwards instantly. Diane looked at Meliodas, her eyes wide.  
"Harry?" She whispered. "Is that Harry potter?" Meliodas nodded: the black-haired boy matched Dumbledore's description perfectly.  
Hermione said something which must have been the password, because the portrait swung open. The five of them were greeted by a wave of noise.

"Harry!"  
"Ron!"  
"Were you really in a flying car?"  
"Did you get expelled?"  
One of the red-haired twins ran up to them, grinning madly. "Why didn't you tell us you were going in the car? We would have come too!"  
Harry tried to speak. "No - we didn't just-"  
He was cut off by more shouting. Meliodas could see that he was tired and overwhelmed, and decided to give him a hand. He helped Harry edge away to the boys dormetries, where he ran up the spiral staircase and into the second years room. Meliodas followed him.  
When he walked into his room, Harry said, "Thanks for that. And.. who are you?"  
Meliodas grinned. "I'm Meliodas. You weren't in the sorting so you missed what Dumbledore said, but I'm from a different school that got destroyed, so me and my friends are joining Hogwarts." Harry replied with, "Will you be following the second years' timetable?" The dragon sin nodded. "Who else came?" The Griffindor asked.  
"Me and Diane are the only ones in Griffindor, and there's Ban in Slytherin, Elizabeth and King in Hufflepuff, and Merlin and Gowther in Ravenclaw." Harry nodded, and started unpacking his school trunk, when Ron burst into the dormitory, grinning.  
"Wow! They all think we're heroes!" Then he spotted Meliodas, and whispered to Harry, "Um, who's that?" Meliodas left Harry to explain, and walked to his bed. He lay down, without putting on his pajamas, and went to sleep.

When he woke up, Harry, Ron, and the other three boys in there were still asleep. The dragon sin stood up and stretched, and walked straight down to the common room, which was empty other than a few older students who, by the looks of it, had been studying all night. Wondering how long Diane would be, Meliodas sat down in a chair and looked around the common room. Tapestries of witches and wizards were on the walls and, seeing some writing, the demon found out that they were paintings of the heads of Griffindor from the past. However, the blonde dragon sin wasn't really interested in it, so he wondered what Elizabeth was doing right now instead. About ten minutes later, he was joined by Diane and Hermione, who were in a conversation.  
"Hi, ca- Meliodas!" Diane said brightly.  
"Hi," Hermione muttered distractedly. She looked angry about something.

**Notes for the Chapter:**

> I just realized that this was a terrible place to end the chapter but?? Also sorry for the late upload, I was watching a movie with my friend :D  
> Now I have finished my premade chapters the future uploads might be a tiny bit slower, I'm sorry


	5. Chapter 5

**Notes for the Chapter:**

> Merry Christmas!! I hope you all had an amazing day bc you deserve it <3

As the trio walked down to the great hall, they were quick to realise that they were early to wake up. Only a few other students were already eating breakfast, and with relief he noticed that his team (excluding Ban, he noticed with amusement) were all already in the great hall. When they caught sight of each other, the Ravenclaws walked towards the Hufflepuff table, and Meliodas and Diane followed. With an awkward glance, Hermione murmured, "I'll wait for you at the Gryffindor table."   
The sins all met up at the yellow and black table and exchanged greetings.  
"S- Meliodas!" Elizabeth exclaimed with happiness. He smiled, glad to see her again, and took a seat next to her. King gave them a small wave, and looked at the breakfast table in a glum way.   
"It feels so strange without Chastiefol," he mumbled. Diane looked at him with pity and sat next to him.  
Merlin only smirked in greeting, and her companion simply blinked and stared at them.   
The mage, still smiling, said, "I must say, I have to commend this school's magical knowledge. After exploring the library I have found out much that I was confused about before."  
Meliodas smiled at her. "And how is your house?"   
"Just like normal human teenagers. Although they are magical, they don't have much in common with me. Most of them seem unnerved by Gowther, naturally." The smaller sin looked up at his name.  
"I can see why," King muttered under his breath. After this was pointed out, Meliodas did notice that their group was avoided by other students, some of whom were whispering about them, doing a poor job to hide it. As more people walked into the hall, generally in groups, the sins noticed a lone fox strutting towards them.  
"Damn, you guys were up early," Ban yawned as Hawk trotted up behind him.  
Meliodas smirked. "At least some of us remember that we're on a mission," he joked.  
"Hey, look! Those are our timetables!" said Diane with excitement. Just as she had said, each of their heads of houses located the sins to give them a sheet of parchment.   
"First lesson, transfiguration with the Gryffindors," pointed out Gowther, his monotonous voice speaking for the first time making some people jump.   
"So! I guess you're with us!" Meliodas grinned at the two Ravenclaws.   
The group had been eating their breakfast in almost silence when a malicious, strict female voice rung out from further up the hall, although by some magic, the voice was hundred of times louder than it should have been. The voice was filled with such fury that it was hard to distinguish words from it, but they managed to hear about a magic car and the whomping willow, so it was not hard to guess who it was directed at. 

As the four walked into a classroom, Meliodas noticed the teacher from the sorting, professor McGonagall. The group seated themselves near the back, and were joined by the trio that was Harry, Hermione and Ron. His pink-haired comerade was quick to read the memories of one of them. Before he could say anything awkward, the dragon sin quickly intervened.   
"Gowther, Merlin, this is Harry, Hermione and Ron," he said with a smile. The latter three smiled and gave their greetings to the two, returned by Merlin. The ginger teenager leaned across the table.  
"Hey," he said, addressing Gowther, "are you a guy or a girl?"  
Hermione glared at him. "Ron! You can't just ask someone that!"  
"Sorry," he muttered, annoyed. "I can't tell."  
The petite boy simply replied with, "I am a male," which caused the boar's sin to snicker under her breath. A glare from their professor signified the start of the lesson.  
To be honest with himself, Meliodas wasn't interested in this lesson like Merlin, and was glad when they were allowed to try it out with their own wands. Their task was to transform a ladybird into a button, although it seemed that most of the students were paying little or no attention, from the lack of success around the room. Turning to his left, he noticed that Ron was frustratedly brandishing a wand that was snapped in two, and successfully creating sparks and puffs of smoke.   
Noticing his watchfulness, Harry said "He broke it when we arrived at Hogwarts. You probably heard, but we kind of came in a flying car. The whomping willow just happened to be where we landed," he explained guiltily, and the hard stare from Hermione noted that she wasn't happy about this at all.   
"You arrived because the Hogwarts express would not allow you to ride it, correct?" the sin of lust added. "Although you are not sure why." The trio looked at him in suprise at how the Ravenclaw could know this. Merlin gave him a warning glance, willing him to not reveal his magic. He seemed to understand, and went back to casting his wand at the ladybird. Diane snarled in frustration at her bug, which simply scuttled over the table. Unsurprisingly, the mage had already transformed hers, and was observing the others. Hermione, also, had done hers, and looked very proud of herself. Ron was still not close to doing so.  
"You should get a new wand," Meliodas advised.

**Notes for the Chapter:**

> So I'm going to reread chamber of secrets so I get all the stuff in the right order, only the one thing I'm worried about is rewriting the book with different characters, I definitely plan on making differences in the future. Also yes, I'm going to write from other character's points of view, dw


	6. Chapter 6

**Notes for the Chapter:**

> hey! sorry for the long break lol. to make it up to y'all I made this longer than usual so um, enjoy? I got back into both these fandoms so expect more frequent updates lmfao

As a period of charms passed, nothing much happened. Inbetween the second and third lessons, the students were allowed to have a break from lessons and just talk with friends or study. Unsurprisingly, the group of seven met up - less expectantly, a nervous-looking second year walked up to them.  
"E-excuse me?" She stammered, without introducing herself as though she wanted to get away quickly. "Professor Dumbledore asked me to give you this…" Ban snatched a scroll of parchment off her and she practically ran off as he read it aloud.  
"Dear the seven deadly sins and Princess," the fox sin read in a mock-posh voice. "I would like to request that you meet me in my office when the lessons for today have finished. You will find that the password is sherbet lemons, and I trust you to come straight to me. Yours sincerely, Albus Dumbledore." The group glanced at each other.   
"I wonder what he wants to tell us?" King said, with curiousity. 

Glancing down at her timetable, the Princess of Liones noted that she had herbology first with the Gryffindors. Realising this meant that she could be with Meliodas and Diane, she smiled to herself. Going to lessons with King was nice, but she couldn't help missing the sin of wrath - in the tavern, she would be with him all day.   
As the group said their goodbyes and split up on the way to lessons, she found herself walking next to Meliodas. Noticing this as well, he looked up at her and grinned his usual grin, causing her to smile and blush slightly. As she tried to find words to start a conversation, a rather talkative Hufflepuff second year walked intrusively between the lovers.  
"Hello! My name is Justin Finch-Fletchley. You're the foreign students, right? I heard all about you from the other students. I understand that feeling of not knowing many people, I was a muggle-born, you know, although I'm definitely glad I came here! It's great, isn't it?"   
Realising that he was waiting for an answer, Elizabeth smiled. "Yes, it sure is! There's just so much to learn!"  
As the group   
had been talking, they had arrived at the greenhouses for herbology. Lost in thought, she glanced at her companions, and realised that Diane and King would probably be good at this class, with their connections to the Earth and nature. They walked towards their teacher, who Elizabeth remembered being the head of her own house, Hufflepuff. The short teacher had a bandage on her arm and looked more disgruntled than the last time she had seen her. She was followed by another teacher who Elizabeth didn't know. He possessed a sparkly, wide grin and was occasionally saying something to the other teacher, who seemed visibly irritated by the overconfident man. As the class neared their teacher, they managed to overhear part of the conversion.  
"... and that's why you don't try to tackle a whomping willow alone! Don't forget to consult an expert in the subject before trying to do something difficult like that - you might remember from one of my books, I single-handedly saved two lovers from one?"   
"He seems a bit full of himself, doesn't he?" Meliodas whispered to his companions, earning a giggle from the Princess. The blond teacher seemed to notice the watching students.  
"But don't think I'm trying to take over your class! Mrs Sprout is still your teacher - but don't be too disappointed, I still have you for defence against the dark arts!"  
Nobody responded out of either disbelief at the amount of self-confidence, or his lack of notice at this. The teacher seemed to take it as awe, instead. When the class began to walk inside, he suddenly pulled Harry Potter aside, to the Wizard's suprise.   
"Don't mind us! I just need to offer young Harry here some important advice. I trust you don't mind, professor?" Without waiting for an answer, he steered Harry away, ignoring the look of annoyance at yet another interruption given by their teacher.  
Meliodas' eyes narrowed, not forgetting their instructions from Dumbledore. However, he continued inside like the rest of the students. His eyes remained fixated on the duo outside, and did do so until the confused-looking boy stumbled inside, and walked over to Ron and Hermione.   
"Right," the irritated Professor Sprout started, "Can we begin now?" 

The trio of wizards were partnered up with the talkative Hufflepuff from before (secretly to Elizabeth's relief) and her and Meliodas with King and Diane. Whatever hope she had had of catching up with her friends vanished when they were instructed to grab fluffy earmuffs. The head of Hufflepuff brought out several plants. Confused, they looked to the Princess like average plants, although the fairy king gaped at them in shock. "Mandrakes," he mouthed, although that meant nothing to Elizabeth, so she turned back to the instructor.

The lesson passed, and the high pitched noise of the screaming plants had made most the students jump - after the lesson, King informed the group of the rarity of them in the Fairy King's forest. The remaining day passed with little interest, until their final lesson - defence against the dark arts. With Gilderoy Lockhart as their professor.

**Notes for the Chapter:**

> thanks for reading!! I'm going to write about a few different characters in the next chapter.


	7. Chapter 7

**Notes for the Chapter:**

> i dont like this chapter,, but its kinda long so i hope that makes up for it lol

Both Diane and Meliodas, of course along with Harry and Ron, did not like the blonde professor. Although it seemed that most of the Gryffindor girls admired him, Hermione Granger included, some of the people in Harry’s house either found him annoying or incompetent - or both. He couldn’t help noticing the duo that was Dean Thomas and Seamus Finnigan were trying hard not to laugh as the vain professor strode in and announced that the lesson would begin with a quiz on Lockhart himself, and Harry honestly couldn’t blame them. He wasn’t surprised when neither he nor Ron got a high score, although the latter made a disbelieving noise when Hermione managed to get a full score. 

For the remainder of the lesson, it was announced that they were to study a dangerous beast. Any hope the class had vanished when he dramatically revealed a mass of angry-looking cornish pixies. Laughter erupted from the front of the classroom.

“Well, lets see how you all can handle them, then!”

Before anyone could shout in panic, hell was unleashed. People hid under desks as books and sheets were shredded, quills and ink were flung out the open window and students fled the carnage as fast as they could. In the scramble to the door, the trio were stuck behind. As Lockhart ran to the door, he hesitated, and glanced back into the classroom. “I’ll leave these last few to you five, then!” Harry, Ron and Hermione gaped at the door, while the other two desperately tried to grab the creatures. 

“Meliodas?” A dark-haired ravenclaw who Harry recognised as one of the transfer students, Merlin, strode in elegantly, followed by her fellow ravenclaw with pink hair, and a slytherin with light blue hair. He couldn’t help wondering why they all had such strange appearances. The woman’s smirk widened. “We were wondering where you two were.” She raised a hand, and the pixies all froze in their place. Hermione gaped at her, impressed. “Come on. We need to see Professor Dumbledore now.” Meliodas hopped over a desk while Diane followed, and the former turned around to give them a grin and a wave in farewell.

Merlin led the sins over to a large gargoyle, where they met King and Elizabeth.

“This statue is the entrance to his office.” The group stared at it for a few minutes.  
“What did they say the password was, again?” Ban asked dryly.  
“Sherbet lemon,” stated the monotonous goat sin, and to his companions’ surprise, they found the statue moving aside. The sin of greed let out a laugh, and strode in, slouching as usual. More cautiously, his companions followed. They stepped onto a sort of moving staircase, which carried the sins up to a beautiful griffin knocker, and the door opened as if the headmaster had been waiting for their arrival. He was seated in a grand chair, and the black-haired potions master, who had presumably been pacing, stood staring at the new arrivals with distrust.

“The ‘transfer students’,” he spat with irritation. Meliodas stared at the man with equally narrowed eyes, and he could sense some of his team doing the same. Surely dumbledore wouldn’t hire someone dangerous? Either way, it was still safe to-

“He can be trusted,” said the headmaster, calmly yet firmly. Meliodas glanced towards him, slightly questioningly.

“It’s true,” confirmed Gowther, his amber eyes shifting to look at Meliodas and the others. He nodded at this. However, Snape stepped forward at this. 

“And what makes you believe he can be trustworthy and not the headmaster?” he drawled coldly. 

“Gowther can’t lie, and even if he could, he has no reason to,” the dragon sin plainly said.

The head of slytherin whipped his head around to lock stares with Dumbledore. “I assume you summoned me here to explain this?” A small nod of confirmation, and a blink of surprise from Meliodas.

And so the headmaster explained it all. Snape simply sat and listened. And when he was finished, he simply stared at the group for a minute. 

“And may I ask about each of your powers?” he then questioned, his voice deathly quiet. The sins - and Elizabeth - exchanged a long look, and then the latter stepped forwards.

“I am part goddess, and although I may not be able to fight like sir Meliodas and others, my powers are in healing.”  
“So like some sort of a healer?” Elizabeth had heard the word in a lesson, and so nodded. 

Ban’s drawl cut her off. “I’m an immortal~” he sang. The professor’s eyes lit up slightly although he did not offer a question this time. The fairy king floated over, Diane by his side.  
“I am a fairy, so I can wield my weapon through my mind. I may also use my magical power to make a small injury large, or to make a tree grow quickly, things like that.”  
Diane smiled and winked. “I’m normally a giant but this amulet Merlin gave me keeps me small right now!” Snape nodded, still unmoving. 

The lust sin struck a pose. “My magical power is invasion! I can both read and change other people’s memories.” At this the potions master stepped forward, allowing the smallest amount of shock to creep onto his face.  
“You’re a Legilimens.” The drawling voice stated. Gowther simply stared up at Snape, his head slightly tilted to one side.  
“My magic is not the same as that, as I can read your thoughts despite you being trained in occlumency.”  
The addressed strode back to professor Dumbledore. “These people are dangerous. I should hope you have a good reason for this.” He inclined his head slightly in response.

The mage glanced at Meliodas, who gave her a nod in confirmation.   
“I myself study magic not unlike the students at this school, and our dear captain here wields demon magic, and an amount of physical strength.”  
This statement was met with silence. And then, “Would it be safe to assume that you hired these, ah, knights, to protect the Potter boy?”  
The headmaster inclined his head. “These are dark times, Severus. Voldemort is even more desperate to return after his defeat last year, and I’m afraid that Harry’s luck will not hold for a third time.”

**Notes for the Chapter:**

> I was looking back on my much older chapters,, and they were sO cringy i wrote Dumbledore terribly jhdsbdjhsb
> 
> Thank you so so much for all the support on this so far!! i really appreciate it <3  
> And i am in love with both these fandoms so much,, so i rlly hope i get to finish this even tho im so slow lol


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